Process for recovering heavy metal using insoluble starch-xanthates

Abstract

A precoat layer comprising a mixture of insoluble starch-xanthate and a filter-aid is deposited on a filter leaf through which a solution containing a heavy metal flows in a continuous stream and insoluble starch-xanthate and filter-aid are continuously added upstream of the precoat layer.

What is claimed: 
     
       1. A process for recovering heavy metal from a continuous stream of water containing said metal in concentrations which vary from time to time between minimum and maximum levels, comprising causing said stream of water to flow through a filter element,   coating said filter element with a mixture of diatomaceous earth and insoluble starch-xanthate, the relative amounts of diatomaceous earth and insoluble starch-xanthate combined in said mixture being in the range of 1.75 to 3.0 parts diatomaceous earth to one part insoluble starch-xanthate,   continuously adding to said stream upstream of said filter element diatomaceous earth and insoluble starch-xanthate, the relative amounts of diatomaceous earth and insoluble starch-xanthate added to said stream being in the range of 1.75 to 3.0 parts diatomaceous earth to one part insoluble starch-xanthate,   the amount of said insoluble starch-xanthate added to said stream upstream of said filter element being sufficient to react with all of said metal contained in said stream at said minimum concentration level to form upstream of said filter element a complex including all of the metal contained in said stream at said minimum concentration level, but said amount being insufficient to react with all of said metal in said stream at said maximum concentration level.   
     
     
       2. A process according to claim 1 where the amounts of diatomaceous earth and insoluble starch-xanthate in said mixture is in the range of about 1.75 to 2.0 parts diatomaceous earth to one part insoluble starch-xanthate.   
     
     
       3. A process according to claim 1 wherein said metal is copper.   
     
     
       4. A process according to claim 1 wherein said metal is nickel.   
     
     
       5. A process according to claim 1 wherein said metal is zinc.